SPC MD 180

MD 0180 CONCERNING WINTER MIXED PRECIPITATION FOR NERN TX PANHANDLE…ERN OK PANHANDLE…NWRN AND N-CNTRL OK…SRN KS


MESOSCALE DISCUSSION 0180
NWS STORM PREDICTION CENTER NORMAN OK
1149 PM CST WED FEB 20 2013

AREAS AFFECTED...NERN TX PANHANDLE...ERN OK PANHANDLE...NWRN AND
N-CNTRL OK...SRN KS

CONCERNING...WINTER MIXED PRECIPITATION

VALID 210549Z - 211145Z

SUMMARY...INCREASING PRECIPITATION RATES...WITH PREDOMINANTLY MIXED
P-TYPES INITIALLY...ARE FORECAST THROUGH EARLY THU MORNING. A
TRANSITION TO HEAVY SNOWFALL MAY OCCUR IN A SW-NE CORRIDOR FROM THE
NERN TX PANHANDLE INTO S-CNTRL KS...WHILE A MORE UNCERTAIN/MIXED
P-TYPE IS LIKELY ACROSS NWRN AND N-CNTRL OK.

DISCUSSION...STRONG ASCENT ASSOCIATED WITH UPPER DIVERGENCE AHEAD OF
A SWRN CONUS UPPER TROUGH IS OVERSPREADING RICHER TROPOSPHERIC
MOISTURE ACROSS THE SRN HIGH PLAINS...RESULTING IN AN INCREASE IN
PRECIPITATION /PER RECENT RADAR LOOPS/. THIS TREND IS EXPECTED TO
CONTINUE...WITH WIDESPREAD PRECIPITATION DEVELOPING ACROSS THE ERN
TX/OK PANHANDLES AND INTO WRN OK...AS THE AFOREMENTIONED LIFT
BECOMES JUXTAPOSED WITH ISENTROPIC ASCENT FOCUSED WITHIN THE 300-306
K LAYER.

THE SFC FREEZING LINE...POSITIONED FROM 40 ESE GUY TO 30 E AVK PER
05Z OBSERVATIONS...IS FORECAST TO SLOWLY SAG SWD AS MODEST BOUNDARY
LAYER COOLING OCCURS /AS SUPPORTED BY 04Z RAP AND 00Z NAM FORECAST
SOUNDINGS/. HOWEVER...A WARM NOSE CENTERED NEAR THE 800 MB LEVEL IS
EXPECTED TO RESULT IN AN INITIALLY MIXED P-TYPES. AS THE LARGE-SCALE
SYSTEM AND PRECEDING LOW-LEVEL JET SHIFT EWD...COOLING WITHIN THIS
LAYER SHOULD EVENTUALLY LEAD TO A TRANSITION TO ALL SNOW ACROSS A
CORRIDOR FROM THE NERN TX PANHANDLE INTO S-CNTRL KS...WITH RATES OF
1-1.5 INCH PER HR POSSIBLE. FARTHER S...THE WARM LAYER CENTERED NEAR
800 MB IS EXPECTED TO REMAIN MORE PRONOUNCED AND ABOVE
FREEZING...WHILE NEAR- TO SUB-FREEZING SFC TEMPERATURES MAY FAVOR
P-TYPES OF FREEZING RAIN AND/OR SLEET. CONVECTIVE ENHANCEMENT OF
PRECIPITATION RATES IS ALSO POSSIBLE GIVEN THE PRESENCE OF STEEP
MID-LEVEL LAPSE RATES AND ONGOING LIGHTNING S OF THE HIGHLIGHTED
AREA.

..ROGERS.. 02/21/2013

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...ICT...OUN...DDC...AMA...

LAT...LON   37169689 35789859 35170012 35130073 35510116 36020124
            36620096 37140032 37479959 37669894 37699771 37169689

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